Update Custom Elements API to new names.

LayoutTests/fast/dom/custom/document-register-svg-extends.html

Index: LayoutTests/fast/dom/custom/document-register-svg-extends.html
diff --git a/LayoutTests/fast/dom/custom/document-register-svg-extends.html b/LayoutTests/fast/dom/custom/document-register-svg-extends.html
index 0a8126c6b910eeba0317d339e9cad121a830a728..1b5982a0bebae8c8e9a600e8a22f05cffbe3b531 100644
--- a/LayoutTests/fast/dom/custom/document-register-svg-extends.html
+++ b/LayoutTests/fast/dom/custom/document-register-svg-extends.html
@@ -7,10 +7,10 @@ test(function () {
     var proto = Object.create(SVGGElement.prototype);
 
     assert_throws('INVALID_CHARACTER_ERR', function() {
-        document.register('x-foo', {prototype: proto});
+        document.registerElement('x-foo', {prototype: proto});
     }, 'register of an SVG element requires the extends parameter');
 
-    var XFoo = document.register('x-foo', {prototype: proto, extends: 'g'});
+    var XFoo = document.registerElement('x-foo', {prototype: proto, extends: 'g'});
 
     var created = new XFoo();
     assert_true(created instanceof SVGGElement, 'created element should be an SVG element');